[tip: timers/core] tick/nohz: Remove duplicate between lowres and highres handlers

tip-bot2 for Peng Liu
2024-02-26T22:24:42Z

The following commit has been merged into the timers/core branch of tip:

Commit-ID: 37263ba0c44b13b2025398ac81919df9f0a91368
Gitweb: https://git.kernel.org/tip/37263ba0c44b13b2025398ac81919df9f0a91368
Author: Peng Liu <liupeng17@lenovo.com>
AuthorDate: Sun, 25 Feb 2024 23:54:54 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 26 Feb 2024 11:37:31 +01:00

tick/nohz: Remove duplicate between lowres and highres handlers

tick_nohz_lowres_handler() does the same work as
tick_nohz_highres_handler() plus the clockevent device reprogramming, so
make the former reuse the latter and rename it accordingly.

Signed-off-by: Peng Liu <liupeng17@lenovo.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240225225508.11587-3-frederic@kernel.org

---
kernel/time/tick-sched.c | 96 ++++++++++++++-------------------------
1 file changed, 36 insertions(+), 60 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index d490165..88c992f 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -255,6 +255,40 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING);
}
+
+/*
+ * We rearm the timer until we get disabled by the idle code.
+ * Called with interrupts disabled.
+ */
+static enum hrtimer_restart tick_nohz_handler(struct hrtimer *timer)
+{
+ struct tick_sched *ts = container_of(timer, struct tick_sched, sched_timer);
+ struct pt_regs *regs = get_irq_regs();
+ ktime_t now = ktime_get();
+
+ tick_sched_do_timer(ts, now);
+
+ /*
+ * Do not call when we are not in IRQ context and have
+ * no valid 'regs' pointer
+ */
+ if (regs)
+ tick_sched_handle(ts, regs);
+ else
+ ts->next_tick = 0;
+
+ /*
+ * In dynticks mode, tick reprogram is deferred:
+ * - to the idle task if in dynticks-idle
+ * - to IRQ exit if in full-dynticks.
+ */
+ if (unlikely(ts->tick_stopped))
+ return HRTIMER_NORESTART;
+
+ hrtimer_forward(timer, now, TICK_NSEC);
+
+ return HRTIMER_RESTART;
+}
#endif

#ifdef CONFIG_NO_HZ_FULL
@@ -1429,31 +1463,15 @@ void tick_nohz_idle_exit(void)
* at the clockevent level. hrtimer can't be used instead, because its
* infrastructure actually relies on the tick itself as a backend in
* low-resolution mode (see hrtimer_run_queues()).
- *
- * This low-resolution handler still makes use of some hrtimer APIs meanwhile
- * for convenience with expiration calculation and forwarding.
*/
static void tick_nohz_lowres_handler(struct clock_event_device *dev)
{
struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
- struct pt_regs *regs = get_irq_regs();
- ktime_t now = ktime_get();

dev->next_event = KTIME_MAX;

- tick_sched_do_timer(ts, now);
- tick_sched_handle(ts, regs);
-
- /*
- * In dynticks mode, tick reprogram is deferred:
- * - to the idle task if in dynticks-idle
- * - to IRQ exit if in full-dynticks.
- */
- if (likely(!ts->tick_stopped)) {
- hrtimer_forward(&ts->sched_timer, now, TICK_NSEC);
+ if (likely(tick_nohz_handler(&ts->sched_timer) == HRTIMER_RESTART))
tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1);
- }
-
}

static inline void tick_nohz_activate(struct tick_sched *ts, int mode)
@@ -1522,48 +1540,6 @@ void tick_irq_enter(void)
tick_nohz_irq_enter();
}

-/*
- * High resolution timer specific code
- */
-#ifdef CONFIG_HIGH_RES_TIMERS
-/*
- * We rearm the timer until we get disabled by the idle code.
- * Called with interrupts disabled.
- */
-static enum hrtimer_restart tick_nohz_highres_handler(struct hrtimer *timer)
-{
- struct tick_sched *ts =
- container_of(timer, struct tick_sched, sched_timer);
- struct pt_regs *regs = get_irq_regs();
- ktime_t now = ktime_get();
-
- tick_sched_do_timer(ts, now);
-
- /*
- * Do not call when we are not in IRQ context and have
- * no valid 'regs' pointer
- */
- if (regs)
- tick_sched_handle(ts, regs);
- else
- ts->next_tick = 0;
-
- /*
- * In dynticks mode, tick reprogram is deferred:
- * - to the idle task if in dynticks-idle
- * - to IRQ exit if in full-dynticks.
- */
- if (unlikely(ts->tick_stopped))
- return HRTIMER_NORESTART;
-
- hrtimer_forward(timer, now, TICK_NSEC);
-
- return HRTIMER_RESTART;
-}
-#else
-#define tick_nohz_highres_handler NULL
-#endif /* CONFIG_HIGH_RES_TIMERS */
-
#if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
static int sched_skew_tick;

@@ -1587,7 +1563,7 @@ void tick_setup_sched_timer(int mode)
hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);

if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && mode == NOHZ_MODE_HIGHRES)
- ts->sched_timer.function = tick_nohz_highres_handler;
+ ts->sched_timer.function = tick_nohz_handler;

/* Get the next period (per-CPU) */
hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());